1. Field of the Invention
The present invention relates to a fault and noise tolerant system and method for electronic equipment, and more particularly, to a system and method for tolerating unknown faults and noise in electronic equipment so that a signal generated by the electronic equipment is not influenced by the unknown faults and noise. The present application is based on Korean Patent Application No. 2001-47726, filed Aug. 8, 2001, which is incorporated herein by reference.
2. Description of the Related Art
Electronic equipment such as global positioning systems, inertial navigation systems, motor control systems, engine control systems, communication systems, and speech enhancement and recognition systems generate various types of signals. When unknown faults (such as faults, biases, or maneuvers) or noise occurs in electronic equipment, these signals are mixed with noise or fault signals generated due to the unknown faults.
When a signal generated in an electronic equipment is mixed with a fault signal or noise, a result obtained based on the signal has an error. In order to prevent a result from having an error due to an unknown fault or noise, there has been provided an apparatus which compares a signal generated from a system in which the characteristics of a given electronic equipment are mathematically modeled with a signal actually generated from the given electronic equipment to detect presence or absence of an unknown fault and/or noise.
However, the conventional apparatus only determines whether an unknown fault or noise occurs in the electronic equipment and reports the result of determination to allow an operator of the electronic equipment to take proper measures or to stop the operation of the electronic equipment. The conventional apparatus, however, does not obtain an original signal which does not include a fault signal or noise.
To solve the above-described problems, it is an object of the present invention to provide a fault and noise tolerant system and method for obtaining an original signal which is not influenced by a fault or noise occurring in an electronic equipment.
To achieve the above object of the present invention, there is provided a fault and noise tolerant system for electronic equipment. The fault and noise tolerant system includes a first estimation filter for estimating an original signal from a signal output from the electronic equipment, considering noise of the electronic equipment; a second estimation filter for estimating the original signal and a fault signal from the signal output from the electronic equipment, considering a fault and the noise; a fault detection unit for detecting presence or absence of a fault in the electronic equipment based on the estimated fault signal received from the second estimation filter; and a selection unit for selecting one of the estimated original signals from the first and second estimation filters, respectively, according to the result of detection of the fault detection unit.
Preferably, the first estimation filter is configured based on a state space model considering the noise without considering the fault with respect to the signal output from the electronic equipment, and the second estimation filter is configured based on a state space model considering both the noise and the fault with respect to the signal output from the electronic equipment.
Preferably, the fault detection unit includes a scalar value detector for detecting a scalar value of the estimated fault signal received from the second estimation filter, and a comparator for comparing the scalar value with a predetermined threshold value and outputting the result of comparison as the result of detection of the presence or absence of a fault.
Preferably, the comparator outputs the result of detection so that the selection unit selects the estimated original signal from the first estimation filter when the scalar value does not exceed the threshold value and selects the estimated original signal from the second estimation filter when the scalar value exceeds the threshold value.
To achieve the above object of the present invention, there is also provided a fault and noise tolerant method for electronic equipment, including the steps of estimating an original signal from a signal applied from the electronic equipment, considering noise of the electronic equipment; estimating the original signal and a fault signal from the signal applied from the electronic equipment, considering a fault signal and the noise; detecting presence or absence of a fault in the electronic equipment based on the estimated fault signal; and selecting the result of estimation considering the noise of the electronic equipment as a signal generated from the electronic equipment when there is no fault in the electronic equipment and selecting the result of estimation considering both noise and fault of the electronic equipment as the signal generated from the electronic equipment when there is any fault in the electronic equipment.
Preferably, the step of detecting presence or absence of a fault includes the steps of detecting a scalar value of the estimated fault signal; comparing the detected scalar value with a predetermined threshold value; if the detected scalar value does not exceed the predetermined threshold value, outputting a signal for selecting the result of estimation considering the noise of the electronic equipment as the result of detection of presence or absence of a fault; and if the detected scalar value exceeds the predetermined threshold value, outputting a signal for selecting the result of estimation considering both noise and fault of the electronic equipment as the result of detection of presence or absence of a fault.
Preferably, the fault and noise tolerant method further includes the step of providing the result of selection to the electronic equipment.